C# 使用事件处理程序创建事件列表，以向事件列表添加或删除处理程序

Question

In an application, I have a rather large list of events and their assigned handlers such as:

...
Resize += FormMain_Resize;
ResizeEnd += FormMain_ResizeEnd;
...

What I am wanting to do is add all these items into a list so that I can iterate through them to unassign (turn them off), do a bunch of work, then iterate through the list again to reassign the event handlers to the events.

To date I've not found any relevant information dealing with creating an actual list and their assigned event handlers. Is this a thing I should not be attempting?

I created a class as follows:

public class EventWHandler
{
    public EventWHandler(EventHandler e, EventHandler m)
    {
        EventItem = e;
        Method = m;
    }

    public EventHandler EventItem { get; private set; }
    public EventHandler Method { get; private set; }

    public void Listen()
    {
        EventItem += Method;
    }

    public void UnListen()
    {
        EventItem -= Method;
    }
}

With the idea of creating a list of the above class with:

list.Add(new EventWHandler(Resize, FormMain_Resize));

However, this will not work without some tweaking - as I was not able to make an object reference to the event (and used EventHandler for demonstration)

Is there a better way to iterate through a specified list of events and their handlers?

(Note: I'm not wanting to iterate through ALL events nor ALL of an event's handlers - just a specified list.)

(Note: Using .net 4.7 - project constraints)

Answer 1

I think you may want System.Collections.ObjectModel.ObservableCollection<EventHandler> and System.Delegate classes

You should use ObservableCollection<T> class to update the properties when the list is modified, added, removed, or replaced.

I think it would work.

using System.Collections.ObjectModel;
using System.Collections.Specialized;

public class EventWHandler : ObservableCollection<EventHandler>
{
    public EventHandler CombinedItem { get; private set; }

    protected override void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
    {;
        if (e.NewItems != null)
            CombinedItem = (EventHandler)Delegate.Combine(e.NewItems.Cast<EventHandler>().ToArray());
        base.OnCollectionChanged(e)
    }
}

In use, You don't need to unassign and then assign. Adding the EventHandler will change CombinedItem immediately;

EventWHandler ewh = new EventWHandler()
{
    Resize,
    FormMain_Resize
};
ewh.Add(Native_Resize);
ewh.Remove(Native_Resize);

this.Resize += ewh.CombinedItem;

Also, read these references:
Delegate Methods ,
ObservableCollection ,
NotifyCollectionChangedEventArgs